Many of the largest organisations already use it in their daily operations. It is extensively used both within corporate networks, and for communication with destinations attached to public networks. It hasn't always been called "ISDN" though. ISDN has often hidden behind a brand name or behind the name of the signalling protocol that implements it. In the UK, for instance, we have seen ISDN appear under the guise of Single and Multi-line IDA, 2100 Premier service, DPNSS, and DASS. Now ISDN is promoted as ISDN2 and ISDN30 by BT, and as ISDN132 by Cable & Wirelesss. The signalling systems DPNSS and DASS have been joined by QSIG and Q931. EuroISDN is often mentioned. It is however the services provided, that distinguish ISDN from other types of telecommunications network. Given that many large organisations already use ISDN, why is it appropriate to consider ISDN again?
Firstly, there are, for the first time in the history of telecommunications, dial-up digital 64 kbit/s services available on a wide geographical basis. Not only are these services available nationally throughout the UK but they are also available to at least 35 other countries. These services offer the opportunity to mix voice and data transmissions across the public network, thus opening the door for multimedia communications. Communications are no longer constrained by the need to adapt digital signals so they can be carried over analogue networks. Compared to the PSTN, ISDN offers improved network features, higher quality lines, and shorter call establishment times. Equally important is the fact that user interfaces to ISDN are standardised. In Europe, they will become increasingly harmonious as network operators progressively migrate towards "EuroISDN". The trans-European ISDN will assist the competitive operation of the Single European Market. It will increasingly permit the exchange of digital information at higher speed than hitherto possible over the PSTN.
There is a second reason why it is appropriate to consider ISDN again. As we have already said, most large organisations today use some form of ISDN in their basic communications' infrastructure. We believe though that the scope of such improvements to date has been restricted to those aspects fundamental to the replacement of analogue technology by digital technology. Improvement has centred on aspects such as transmission quality, call establishment time, quality of service, and cost. These aspects are of course important to telecommunications managers and their employers, but the degree of improvement that can be effected is finite. In our view further and repeated efficiency gains can only come about through applications based on ISDN implemented at the departmental level. It is the availability of ISDN's "Basic Access" (either behind PABX or directly from public networks) and the availability of ISDN applications programming interfaces that makes further consideration timely.
It is not just departments within large organisations that can achieve improvement by using ISDN. Small and medium sized enterprises (SME), even if they do not have a corporate network or telecommunications manager of their own, can also benefit from the potential of ISDN applications. SMEs want answers to the same questions facing a department in a large organisation. The main question is "When can ISDN be cost effective to use?".
So many different situations in so many different industries make this a difficult question to answer. It is the same as asking "when can it be cost effective to use a PC?" Like a PC, ISDN is a general purpose tool. It is the packages on top of ISDN and the uses to which they are put that determine cost effectiveness. Each situation has to be analysed and judged on its own merits.
Looked at from the management viewpoint, there are two principal ways of achieving improvements in business efficiency. The first is to identify a specific business process that is not cost effective and to make improvements to it. Using an example from the PC revolution, this is akin to identifying that the efficiency of the typing pool can be improved by replacing all the typewriters with PCs and a word-processing package. It is not the PC per se that causes the improvement; it is the word-processing package and its application to the typing/proofing/retyping process that causes the improvement.
The second way of achieving improvements occurs when a technology is made generally available within an organisation. Individuals and/or departments experiment with it as a potential solution to their daily problems, and ideas for efficiency improvement occur. This is what happened with PCs. As a result, a PC has become "standard fit" for every new desk in many offices. We are not necessarily suggesting every desk should have ISDN fitted to it. However, "taking ISDN to the desk", as distinct from using it for accessing external networks, is the next evolutionary step.
In practice, both mechanisms occur in most organisations. In the first case we carefully analyse a process to identify the desired improvements, the means of achieving them, and the cost of doing so. This has nothing at all to do with ISDN; it is traditional process improvement using the techniques of Total Quality Management, Business Process Re-engineering, or Continuous Improvement. In undertaking such analyses there are, however, some guidelines that can be used to help decide whether ISDN is a potential solution. These are:
Perhaps your organisation should consider applying ISDN to solve a problem if it achieves 1 or more of the following benefits:
As a rule of thumb, ISDN is best suited to applications involving the occasional transmission of large amounts of data, or to applications involving short but infrequent transactions. Transmitting the content of a newspaper from the editorial office to the printers, and retail credit authorisations, are good uses of ISDN. There is less advantage in using ISDN for, for example, on-line database enquiries where the amounts of data are small and most of the transaction time is actually human thinking time. However, each case is different and the goals to be satisfied will vary.
Many uses are concerned with making existing applications perform "better" i.e. with more functionality, faster, more reliably, or at lower cost. Others are new applications that have not previously been considered as viable. We believe there are four general classes of application, as follows:
Firstly, there is what we would call the traditional communications applications. This class covers most of the present cases comms managers know and love; for example, modem replacement, LAN bridging, remote access, Front End Processor to WAN connectivity, PC/EPOS connectivity, bandwidth on demand, inverse multiplexing, private voice networks. By and large these applications are "technology replacement" applications. That is to say, the use of ISDN allows the application to be performed better than it could have been performed with the technology it replaces.
The second class of applications are the standby applications. Standby applications of ISDN include disaster recovery, network overflow, leased line backup, multiplexor backup. Applications in this class are characterised by the fact that they are all "protective" applications. They are not invoked until some abnormal event occurs.
Delivery applications, for moving information from one place to another, include facsimile, file transfer, video surveillance, broadcasting, document imaging, picture imaging, electronic letter. All these examples are characterised by the fact that they are more or less one way information flows, like the postal service.
Finally, there are the interactive applications. As well as plain old telephony, this class includes new, exciting, and innovative applications such as desktop conferencing, videotelephony, videoconferencing, telepresence, credit authorisation, and computer based training. Some of these applications have, without the availability of 64 kbit/s dial-up connections, previously been considered to be impractical. The tremendous advances in computing power, multimedia peripherals and software functionality, coupled with the ability to use dial-up high-speed data channels to an increasing number of destinations opens the door for changing the way we do business. Just as the fax machine changed the way we communicate in the 1980s, so will ISDN interactive applications change it again.
Figures from BT indicate traditional communications applications and standby applications have accounted for about 90% of the usage of ISDN channels to date. By the end of the decade we can expect to see these classes of application accounting for only about 25% of usage, with delivery and interactive applications accounting for the other 75%.
Any of the applications in these 4 classes can be applied to solve common business problems in either a tactical or a strategic manner. Tactical applications, for example, include:
Strategic uses of ISDN may include:
With the launching of EuroISDN and the availability of standardised programming environments to support the development of software for ISDN applications, ISDN appears to have finally come of age. Prices are falling and this, coupled with the availability of an increasing variety of ISDN based applications, is helping to drive the take-up of ISDN. To gain the fullest benefit, organisations need to include ISDN in their list of tools available for resolving problems. The biggest benefits of ISDN have yet to be reaped at the desktop.
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Copyright © PQM Consultants 1998. This page was last updated on 27 May 1998.